Method and device for providing a mobile device with service continuity over multiple access networks

ABSTRACT

Aspects of the subject disclosure may include, for example, registering with a first access network to generate a first registration, detecting a triggering event, and registering with a second access network to generate a second registration while maintaining the first registration with the first access network. Other embodiments are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/299,466, filed Jun. 9, 2014, which claims the benefit of U.S.Provisional Application No. 61/983,435, filed Apr. 23, 2014, which areincorporated herein by reference in their entirety.

FIELD OF THE DISCLOSURE

The subject disclosure relates to a method and device for providing amobile device with service continuity over multiple access networks.

BACKGROUND

Communication of voice, video, messaging and/or data can be performedover different types of networks utilizing different accesstechnologies. These access networks and access technologies havebenefits, as well as detriments, when compared to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying drawings, which are notnecessarily drawn to scale, and wherein:

FIG. 1 depicts an illustrative embodiment of a system that provides forservice continuity over different access networks utilizingco-registration;

FIG. 2 depicts an illustrative embodiment of a system that provides forservice continuity over a Radio Access Network (RAN) and WiFi networkutilizing co-registration;

FIG. 3 depicts an illustrative embodiment of signal flow 300 in a pullmethod for service continuity from a RAN to a WiFi network

FIG. 4 depicts an illustrative embodiment of signal flow 400 in a pullmethod for service continuity from a WiFi network to a RAN.

FIG. 5 depicts an illustrative embodiment of signal flow 500 in a pushmethod for service continuity from a RAN to a WiFi network.

FIG. 6 depicts an illustrative embodiment of signal flow 600 in a pushmethod for service continuity from a WiFi network to a RAN.

FIG. 7 depicts an illustrative embodiment of a method used in portionsof the systems described in FIGS. 1 and 2 to enable service continuityutilizing co-registration;

FIG. 8 depicts an illustrative embodiment of a communication system thatprovides media services including continuity of services for acommunication device;

FIG. 9 depicts an illustrative embodiment of a communication device; and

FIG. 10 is a diagrammatic representation of a machine in the form of acomputer system within which a set of instructions, when executed, maycause the machine to perform any one or more of the methods describedherein.

DETAILED DESCRIPTION

The subject disclosure describes, among other things, illustrativeembodiments for providing service continuity for a communication deviceover different access networks. One or more of the exemplary embodimentscan provide end to end Internet Protocol Multimedia System (IMS) servicelayer adjustments to enable seamless service offerings across differentaccess networks. Other embodiments are described in the subjectdisclosure.

One or more aspects of the subject disclosure can supports dual ormultiple registrations for each (or some) of the available accessnetworks (e.g., within reach and acceptable credential) of thecommunication device. The registration can be of a device to a networkto enable any number of communication services, including voice, video,data and/or messaging. The registrations can be of various types, suchas a registration related to the OSI layers (e.g., one or more of layers3-7 of the OSI model) including related to the user application, device,or the user. Registration can include re-establishing a communicationrelationship, such as based on a user application, user device and/oruser. Registration can include associating a user to a service profile(e.g., billing, features, priorities, and so forth). Registration caninclude enabling an application or content service. Registration caninclude associating a user to a group (e.g., social media).

One or more aspects of the subject disclosure can include a SessionInitiation Protocol (SIP) implementation that supports dual or multipleSIP registrations for each (or some) of the available access networks(e.g., within reach and acceptable credential) of the communicationdevice. The communication device may be referred to herein as a mobiledevice, however, one or more of the exemplary embodiments can beutilized with various types of communication devices (e.g., fixed ormobile end user devices including smart phones, tablets, laptopcomputers, PDAs, desktop computers, vehicle computing devices, and soforth) that provide wireless voice, video, messaging and/or dataservices. One or more of the exemplary embodiments can provide for SIPregistration procedures at the mobile device internal SIP platformand/or at the operator's IMS Core Network (CN).

One or more of the exemplary embodiments can enable an end user deviceto provide service continuity when transferring to different accessnetworks where co-registration has occurred with those different accessnetworks. The service continuity can include providing the same service,such as transferring a voice/video call over different access networks,or can including providing different services such as starting with avoice call over a first access network and (based on co-registration)switching to a video call over a second access network.

One or more of the exemplary embodiments can support multiple SIPregistrations at the device platform using the same IP MultimediaService Identity Module (ISIM) secret or Ki (subscriber key) for each(or a selected group) of accessible access networks (e.g., both reachand security credential), such as a Macro LTE RAN and a WiFi hotspot.The multiple SIP registrations can be maintained simultaneously asapplicable to the same SIP Registrar in the IMS CN.

Some of the exemplary embodiments are described with respect to a SIPregistration that enables co-pending registration for multiple accessnetworks. One or more of the exemplary embodiments can provide for aco-registration process for multiple access networks that utilizesprotocols, standards or techniques other than SIP to enable an end userdevice (e.g., via dedicated or non-dedicated user agents) to initiateand maintain at the same time two or more registrations for differentaccess networks.

One or more of the exemplary embodiments can enable co-registration ofthe same types of access networks that are otherwise different networks,such as co-registration of first and second WiFi access networks thatare managed by different service providers. The end user device and/orthe network(s) can then determine which of the access networks will beutilized for maintaining service continuity when the access networkswitch occurs, such as based on user preferences, service provideragreements with each other, network conditions at each of the accessnetworks, and so forth.

One or more of the exemplary embodiments can utilize a co-registrationprocess to enable service continuity over multiple access networks wherethe service is adjusted responsive to the switching between accessnetworks. As an example, an end user device may initiate a voice callcommunication session utilizing a first access network. Aco-registration of a second access network (while the registration ofthe first access network is maintained) can occur such as during thecommunication session. A triggering event can be detected causing atransfer of the communication session from the first access network tothe second access network. Additionally, the communication session canbe adjusted to include video conferencing over the second accessnetwork. The adjustment of the type of service (in this example from avoice call to a voice/video call) at the second access network can bebased on a number of factors, such as signal quality, costs, subscriberagreements, end user preferences, network traffic conditions, devicecompatibility, and so forth.

One or more of the exemplary embodiments can enable, such as at thedevice platform, the device Native Dialer or other connectivity agent toinitiate a communication session, such as an IMS call via an SIP Inviteon the appropriate or desired transport for Mobile Originated (MO) call.The selection of the appropriate or desired access network can be madeby the mobile device and/or the network, including based on user'spreference, end user performance parameters, network preferences, and/ornetwork performance parameters (e.g., via an algorithmic computation ofperformance metrics).

One or more of the exemplary embodiments can, such as at the deviceplatform, support using a derived IMS Private ID (IMPI) from the ISIMmodule's IMPI parameter (e.g., imsi_wifi@private.serviceprovidername.netwhere “_wifi” is the added suffix and thus derived.

One or more of the exemplary embodiments can, such as at the IMS CN,support multiple SIP Registrations to the same IMS Proxy Server frommultiple User Agents (UAs) at the same mobile device utilizing the sameIMPU (IMS Public User Id) as for macro RAN (such as a HSPA+, LTE, and soforth) but different IMPIs on the UE.

One or more of the exemplary embodiments can, such as at the IMS CN(e.g., at the IMS Home Subscriber Server (HSS), support management ofsubscriber's secret or key (Ki) to maintain ‘synch state’ of both RANand WiFi access (or other network access) for follow-up registrationand/or (re)-registration.

One or more of the exemplary embodiments can, such as at the IMS CN(e.g., at the IMS-HSS), process the Diameter User Authentication Request(UAR) with different IMPI for a 2nd (or more) SIP Registration such asover WiFi, without (in parallel with the 1^(st) SIP registration overMacro LTE network) nullifying the 1st SIP Registration which was overmacro LTE. The exemplary embodiments can also process subsequent SIPregistration(s) without nullifying earlier SIP registration(s) for othertypes of access networks, including WiMAX networks or wireless localarea networks. One or more of the exemplary embodiments can enable someaccess networks (e.g., a WiFi network) to automatically unregister (suchas after expiration of a timer) without utilizing an activede-registration for that access network. In one or more embodiments, aregistration with RAN can always be maintained while a co-registrationwith other access networks (such as a WiFi network or a WiMAX network)can be selectively maintained. In one or more embodiments, theco-registration with multiple access networks can be selectivelymaintained, such as based on device location, user preferences, deviceperformance parameters, network preferences, network performanceparameters, and so forth. As an example, a mobile device can originallybe registered with a RAN and based on a change of location of the mobiledevice a second registration can occur (such as with a WiFi networkavailable in the new location) while the first registration with the RANis maintained.

One or more of the exemplary embodiments can, such as at the IMS CN,route an incoming call over a preferred access network. This example canbe based on registration states for the different available accessnetworks associated with the SIP Registrar.

One or more of the exemplary embodiments can provide an operator withflexibility to offer IMS services (e.g., VoIP, Video over IP, and soforth) in a manner that facilitates billing and/or conserves macro RANcapacity. One or more of the exemplary embodiments can provide a userwith a higher value user experience depending on the quality of macroRAN coverage such as in a situation where WiFi may offer improvedquality (e.g., in a home environment). One or more of the exemplaryembodiments can enable, via dual or multiple registration, serviceprovider(s) to determine best or better path for the particular serviceor function being requested, such as implementing LTE/RAN functionalityover WiFi when it makes sense (e.g., 911 support functionality).

One or more of the exemplary embodiments can maintain any number ofsimultaneous (e.g., at the same time) SIP registrations to the IMS CN toprovide multiple benefits to the operator and/or to the mobile end user.The exemplary embodiments can be utilized in conjunction with one ormore processes described in the 3GPP TS 24.229 standard, the disclosureof which is hereby incorporated by reference.

One embodiment of the subject disclosure is a device that includes aprocessor; and a memory that stores executable instructions that, whenexecuted by the processor, facilitate performance of operations,including registering with a first access network to generate a firstregistration. The device can detect a triggering event, and can registerwith a second access network (responsive to the detecting of thetriggering event) to generate a second registration while maintainingthe first registration with the first access network.

One embodiment of the subject disclosure includes machine-readablestorage medium, comprising executable instructions that, when executedby a processor of a mobile device, facilitate performance of operations,including determining to transfer a communication session of the mobiledevice from a first access network to a second access network where themobile device is registered with the first and second access networks.The processor can initiate a message from a dedicated user agentcorresponding to one of the first or second access networks, therebycausing the transfer of a communication session from the first accessnetwork to the second access network, where the dedicated user agent isresident on the mobile device, and where the message is one of an INVITEmessage or a REFER-to message.

One embodiment of the subject disclosure is a method that includesreceiving, by a system including a processor, a first registrationmessage initiated from a mobile device. The method includes registering,by the system, the mobile device with a first access network to generatea first registration in response to the first registration message. Themethod includes receiving, by the system, a second registration messageinitiated from the mobile device. The method includes registering, bythe system, the mobile device with a second access network to generate asecond registration in response to the second registration message,where the first registration of the mobile device with the first accessnetwork is maintained by the system.

FIG. 1 depicts an illustrative embodiment of a system 100 that enablesan end user device 110, such as a mobile device, to provide servicecontinuity over multiple access networks, such as network 120 (e.g., amacro RAN and EPC network) and network 130 (e.g., a WiFi Internet accessnetwork) . In this embodiment, the end user device 110 includes hardwareand/or a platform that is capable of running SIP stack simultaneously orin an otherwise overlapping fashion. In one or more embodiments, the enduser device 110 can support dedicated SIP User Agents (UAs) for eachaccessible access network. For example, UA-1 and UA-2 can berespectively dedicated for the Macro RAN and WiFi access, respectively.Any number of dedicated user agents can be utilized. In one or moreembodiments, non-dedicated user agents can be utilized such as a useragent that is applicable to a group of access networks (e.g., accessnetworks that require similar registration processes). In otherembodiments, a combination of dedicated user agent(s) and non-dedicateduser agent(s) can be executed by the end user device 110 to facilitateinteracting with the access networks.

Reference letters B1 and B2 in FIG. 1 indicate SIP REGISTER signalingflow initiated by the UAs over their respective access network, e.g., asneeded and/or as accessible/available. In this embodiment, B1 is a SIPREGISTER over the Macro RAN while B2 is a SIP REGISTER over the WiFinetwork. In this example, the processing of the SIP registrations isdenoted by reference C where a proxy SIP REGISTRAR server 155 in an IMSCore 150 can support processing of both B1 and B2 SIP REGISTER flows andcan maintain the respective states of the registrations for futurecommunication sessions as triggered by a SIP INVITE.

In this embodiment, the SIP REGISTER signaling flow initiated by the UAsover their respective access network can be triggered by various eventswhich can be monitored by the end user device 110, the network(s), orboth. In one embodiment, the triggering event can be based on devicelocation, such as when the end user device 110 moves within a coveragearea of a new access network. As another example, the triggering eventcan be based on an end user preference (e.g., a user prefers to utilizeWiFi over another access network such as due to different billing rates)and/or based on an end user device preference and/or performanceparameter (e.g., falling below a threshold for QoS or signal strengthdetected by the end user device 110, available battery power,compatibility of the end user device with the access network such asdevice capabilities being fully usable with one of the access networks,and so forth). As yet another example, the triggering event can be basedon network preferences and/or network performance parameters. Forinstance, a RAN (e.g., a monitoring system of the RAN) can detect heavynetwork traffic in a particular area and can desire to move a number ofend user devices to alternative access networks, such as to alleviateworkload of one or more network elements associated with an overloadedaccess network. In one embodiment, this movement of end user devices toanother access network(s) can be performed in conjunction with userpreferences and/or end user device performance parameters, such asswitching to a new access network only those devices that have providedauthorization for doing so (e.g., authorization included in a subscriberagreement and/or included in a user profile). Other triggering eventscan also be utilized for initiating a second or more co-registration,including triggering events monitored by the end user device, thenetwork and/or one or more third party entities.

FIG. 2 depicts an illustrative embodiment of a system 200 in whichservice continuity is provided to the end user device 110 for acommunication session that is moved from a RAN network 120 to a WiFinetwork 130. It should be understood that various networks utilizingvarious wireless technologies can be utilized in this embodiment, inaddition to or in place of one or both of the RAN and WiFi networks 120,130. The communication session can be of various types including voice,video, messaging and/or data services. In one embodiment, responsive tothe end user device 110 moving into or towards a WiFi footprint, theWiFi user agent (or other user agent that processes WiFi access networkregistration) can register to the IMS via Internet access with theGlobally Routable User (agent) URI (GRUU). However, the triggering ofthe co-registration can also be based on other factors in conjunctionwith device location or in place of device location, such as networktraffic management, end user preferences, communication session types,service agreements, quality of service management, and so forth. In thisexample, the end user device 110 can be active on a call over RAN accessusing a RAN client. The end user device 110 can detect a WiFi accesswhen the end user device moves into (or toward) the WiFi coverage area.The end user device 110 can register the WiFi client with anotherprivate ID, same Authentication and Key Agreement (AKA) AKA in SIM andGRUU to the IMS core 150 such as via an access session border control250. In one embodiment, the location information utilized as atriggering event can be based on an estimated trajectory of the end userdevice 110, such as initiating a co-registration process according to adetection that the end user device will enter a WiFi coverage area verysoon because the end user device is moving toward the WiFi coverage areaat a particular speed.

In one embodiment utilizing a pull method, the WiFi client can send anInvite with Replace over WiFi access to replace the RAN session. Inanother embodiment utilizing a push method, the RAN client can sendREFER with Refer-to point to the WiFi client. The MMTel ApplicationServer (AS) or other network device can then move the session from theRAN to the WiFi access network. As explained above, the communicationsession can be any type of session including voice, video, messagingand/or data services. The particular types of messages that are utilizedfor the co-registration process and/or for the switching between accessnetworks can vary, such as based on the signaling protocol that is beingutilized.

FIG. 3 depicts an illustrative embodiment of signal flow 300 in a pullmethod for service continuity from a RAN to a WiFi network. In thisexample, the service is a voice call, however, the exemplary embodimentscan be utilized with various services including voice, video, messagingand/or data. The exemplary embodiments can be utilized to provideservice continuity between other types of networks such as a WiMAXnetwork, as well as between more than two access networks such as from aRAN to a WiFi network and back to the RAN or to another access network,such as a WiMAX network.

Signal flow 300 depicts steps 1 which are initiated by the RAN client onthe end user device which result in an active session over the RAN withthe second end user device. In this example, responsive to movement ofthe end user device to a new location (although other triggering eventscan also cause or be a factor in the co-registration occurring), steps 2are performed which are initiated by the WiFi client of the end userdevice and which result in the co-registration (or dual registration inthis example) of the end user device with both the RAN and the WiFinetworks.

In this example of signal flow 300, an automatic movement to the WiFiaccess network can be detected resulting in an INVITE message beinginitiated by the WiFi client in step 3 and further resulting in steps4-10 thereby continuing the communication session over the WiFi accessnetwork. The exemplary embodiments can utilize various triggering eventsfor step 3, such as user preferences, end user device performanceparameters, network preferences, and/or network performance parameters.In one or more embodiments, the signaling can follow in part one or morestandards. For example, one or more of steps 4-10 can be similar tosignaling steps utilized by the 3GPP TS 24.229 standard, such asrecipients of the messages and/or information being transferred in themessages.

FIG. 4 depicts an illustrative embodiment of signal flow 400 in a pullmethod for service continuity from a WiFi network to a RAN. In thisexample, the service is a voice call, however, the exemplary embodimentscan be utilized with various services including voice, video, messagingand/or data. The exemplary embodiments can be utilized to provideservice continuity between other types of networks such as a WiMAXnetwork, as well as between more than two access networks such as from aRAN to a WiFi network and back to the RAN or to another access network,such as a WiMAX network.

Signal flow 400 depicts steps 1 which are initiated by the WiFi clienton the end user device which result in an active session over the WiFinetwork with the second end user device. In this example, the end userdevice is already registered with the RAN and the end user device movesout of or towards the boundary of the WiFi coverage area. An automaticmovement to the RAN can be detected resulting in an INVITE message beinginitiated by the RAN client in step 3 and further resulting in steps4-10 thereby continuing the communication session over the RAN. Theexemplary embodiments can utilize various triggering events for step 3,such as user preferences, end user device performance parameters,network preferences, and/or network performance parameters. In one ormore embodiments, the signaling can follow in part one or morestandards. For example, one or more of steps 4-10 can be similar tosignaling steps utilized by the 3GPP TS 24.229 standard, such asrecipients of the messages and/or information being transferred in themessages.

FIG. 5 depicts an illustrative embodiment of signal flow 500 in a pushmethod for service continuity from a RAN to a WiFi network. In thisexample, the service is a voice call, however, the exemplary embodimentscan be utilized with various services including voice, video, messagingand/or data. The exemplary embodiments can be utilized to provideservice continuity between other types of networks such as a WiMAXnetwork, as well as between more than two access networks such as from aRAN to a WiFi network and back to the RAN or to another access network,such as a WiMAX network.

Signal flow 500 depicts steps 1 which are initiated by the RAN client onthe end user device which result in an active session over the RAN withthe second end user device. In this example, responsive to movement ofthe end user device to a new location (although other triggering eventscan also cause or be a factor in the co-registration occurring), steps 2are performed which are initiated by the WiFi client of the end userdevice and which result in the co-registration (or dual registration inthis example) of the end user device with both the RAN and the WiFinetworks.

In this example of signal flow 500, an automatic movement to the WiFiaccess network can be detected resulting in a REFER-to message beinginitiated by the RAN client in step 3 and further resulting in steps4-10 thereby continuing the communication session over the WiFi accessnetwork. The exemplary embodiments can utilize various triggering eventsfor step 3, such as user preferences, end user device performanceparameters, network preferences, and/or network performance parameters.In one or more embodiments, the signaling can follow in part one or morestandards. For example, one or more of steps 4-10 can be similar tosignaling steps utilized by the 3GPP TS 24.229 standard, such asrecipients of the messages and/or information being transferred in themessages.

FIG. 6 depicts an illustrative embodiment of signal flow 600 in a pushmethod for service continuity from a WiFi network to a RAN. In thisexample, the service is a voice call, however, the exemplary embodimentscan be utilized with various services including voice, video, messagingand/or data. The exemplary embodiments can be utilized to provideservice continuity between other types of networks such as a WiMAXnetwork, as well as between more than two access networks such as from aRAN to a WiFi network and back to the RAN or to another access network,such as a WiMAX network.

Signal flow 600 depicts steps 1 which are initiated by the WiFi clienton the end user device which result in an active session over the WiFinetwork with the second end user device. In this example, the end userdevice moves out of or towards the boundary of the WiFi coverage area.An automatic movement to the RAN can be detected resulting in a REFER-tomessage being initiated by the WiFi client in step 3 and furtherresulting in steps 4-10 thereby continuing the communication sessionover the RAN. The exemplary embodiments can utilize various triggeringevents for step 3, such as user preferences, end user device performanceparameters, network preferences, and/or network performance parameters.In one or more embodiments, the signaling can follow in part one or morestandards. For example, one or more of steps 4-10 can be similar tosignaling steps utilized by the 3GPP TS 24.229 standard, such asrecipients of the messages and/or information being transferred in themessages.

FIG. 7 depicts an illustrative embodiment of a method 700 used by acommunication device, such as a mobile device. At 702, the mobile devicecan register with a first access network, such as a RAN. At 704, atriggering event can be detected. The triggering event can be detectedby various devices, such as by the end user device, a network element,or both. The triggering event can be a location (or change thereof) ofthe mobile device (e.g., moving into or in proximity of or towards acoverage area of a second access network such as a WiFi network coveragearea). The triggering event can also be one or more other criteria orthresholds, such as user preferences, end user device performanceparameters, network preferences, and/or network performance parameters.In one or more embodiments, various monitoring can be performed inconjunction with the determining of the triggering event, such asmonitoring QoS of the RAN service, signal power levels, network traffic,device power consumption, and so forth.

If a triggering event is detected, such as the mobile device has enteredthe coverage area of a second access network then at 706 aco-registration can occur. The co-registration can include maintainingthe registration with the first access network while registering withthe second access network. In one embodiment, the co-registration can beperformed by utilizing the same proxy SIP REGISTRAR server of the IMS CNthat performed the first registration.

At 708, another triggering event can be detected. The triggering eventcan be detected by various devices, such as by the end user device, anetwork element, or both. The triggering event can be an automaticmovement by the end user device to transfer the session to the secondaccess network. The other triggering event can also be one or more othercriteria or thresholds, such as user preferences, end user deviceperformance parameters, network preferences, and/or network performanceparameters. In one or more embodiments, various monitoring can beperformed in conjunction with the determining of the other triggeringevent, such as monitoring QoS of the RAN service, signal power levels,network traffic, device power consumption, and so forth. At 710, thesession can be transferred from the first access network to the secondaccess network, such as transferring a voice, video, messaging and/ordata communication session from the RAN to a WiFi network, or viceversa.

In one embodiment, an AKA order of operation on ISIM can be asfollows: 1) Calculate AK where AK=f5_(K) (RAND); 2) Identify SQN whereSQN=(SQN Å AK) Å AK; 3) Compute XMAC where XMAC=f1K (SQN ∥ RAND ∥ AMF);4) Compare MAC (from AUTN) and XMAC.; 4A) If MAC!=XMAC thenauthentication failure; 4B) If MAC=XMAC then go to next step; 5) VerifyHSS's SQN_(HE) derived from AUTN is within range (32) of the ISIM' sSQN_(MS). 5A) If not within range then synchronization failure, computeAUTS and respond; 5B) If within range then continue to next step; 6)Compute RES and include in “response” parameter in SIP Registrationauthentication header.

In one or more embodiments, multiple forms of media services can beoffered to media devices over wireless technologies according towireless access protocols such as Global System for Mobile or GSM, CodeDivision Multiple Access or CDMA, Time Division Multiple Access or TDMA,Universal Mobile Telecommunications or UMTS, World interoperability forMicrowave or WiMAX, Software Defined Radio or SDR, Long Term Evolutionor LTE, and so on. Other present and next generation wide area wirelessaccess network technologies can be used in one or more embodiments ofthe subject disclosure where the signaling protocol of the service isSIP based or in general supports a registration method prior toinitiating a service data transfer session (e.g., voice, video,messaging and/or data).

FIG. 8 depicts an illustrative embodiment of a communication system 800employing an IP Multimedia Subsystem (IMS) network architecture tofacilitate the combined services of circuit-switched and packet-switchedsystems. Communication system 800 can be overlaid or operably coupledwith systems 100 and 200 of FIGS. 1 and 2 as another representativeembodiment of communication system 800. System 800 enables servicecontinuity for an end user device over multiple access networksutilizing a co-registration process.

Communication system 800 can comprise a Home Subscriber Server (HSS)840, a tElephone NUmber Mapping (ENUM) server 830, and other networkelements of an IMS network 850. The IMS network 850 can establishcommunications between IMS-compliant communication devices (CDs) 801,802, Public Switched Telephone Network (PSTN) CDs 803, 805, andcombinations thereof by way of a Media Gateway Control Function (MGCF)820 coupled to a PSTN network 860. The MGCF 820 need not be used when acommunication session involves IMS CD to IMS CD communications. Acommunication session involving at least one PSTN CD may utilize theMGCF 820.

IMS CDs 801, 802 can register with the IMS network 850 by contacting aProxy Call Session Control Function (P-CSCF) which communicates with aninterrogating CSCF (I-CSCF), which in turn, communicates with a ServingCSCF (S-CSCF) to register the CDs with the HSS 840. To initiate acommunication session between CDs, an originating IMS CD 801 can submita Session Initiation Protocol (SIP INVITE) message to an originatingP-CSCF 804 which communicates with a corresponding originating S-CSCF806. The originating S-CSCF 806 can submit the SIP INVITE message to oneor more application servers (ASs) 817 that can provide a variety ofservices to IMS subscribers.

For example, the application servers 817 can be used to performoriginating call feature treatment functions on the calling party numberreceived by the originating S-CSCF 806 in the SIP INVITE message.Originating treatment functions can include determining whether thecalling party number has international calling services, call IDblocking, calling name blocking, 7-digit dialing, and/or is requestingspecial telephony features (e.g., *72 forward calls, *73 cancel callforwarding, *67 for caller ID blocking, and so on). Based on initialfilter criteria (iFCs) in a subscriber profile associated with a CD, oneor more application servers may be invoked to provide various calloriginating feature services.

Additionally, the originating S-CSCF 806 can submit queries to the ENUMsystem 830 to translate an E.164 telephone number in the SIP INVITEmessage to a SIP Uniform Resource Identifier (URI) if the terminatingcommunication device is IMS-compliant. The SIP URI can be used by anInterrogating CSCF (I-CSCF) 807 to submit a query to the HSS 840 toidentify a terminating S-CSCF 814 associated with a terminating IMS CDsuch as reference 802. Once identified, the I-CSCF 807 can submit theSIP INVITE message to the terminating S-CSCF 814. The terminating S-CSCF814 can then identify a terminating P-CSCF 816 associated with theterminating CD 802. The P-CSCF 816 may then signal the CD 802 toestablish Voice over Internet Protocol (VoIP) communication services,thereby enabling the calling and called parties to engage in voiceand/or data communications. Based on the iFCs in the subscriber profile,one or more application servers may be invoked to provide various callterminating feature services, such as call forwarding, do not disturb,music tones, simultaneous ringing, sequential ringing, etc.

In some instances the aforementioned communication process issymmetrical. Accordingly, the terms “originating” and “terminating” inFIG. 8 may be interchangeable. It is further noted that communicationsystem 800 can be adapted to support video conferencing. In addition,communication system 800 can be adapted to provide the IMS CDs 801, 802with the multimedia and Internet services of communication system 400 ofFIG. 4.

If the terminating communication device is instead a PSTN CD such as CD803 or CD 805 (in instances where the cellular phone only supportscircuit-switched voice communications), the ENUM system 830 can respondwith an unsuccessful address resolution which can cause the originatingS-CSCF 806 to forward the call to the MGCF 820 via a Breakout GatewayControl Function (BGCF) 819. The MGCF 820 can then initiate the call tothe terminating PSTN CD over the PSTN network 860 to enable the callingand called parties to engage in voice and/or data communications.

It is further appreciated that the CDs of FIG. 8 can operate as wirelineor wireless devices. For example, the CDs of FIG. 8 can becommunicatively coupled to a cellular base station 821, a femtocell, aWiFi router, a Digital Enhanced Cordless Telecommunications (DECT) baseunit, or another suitable wireless access unit to establishcommunications with the IMS network 850 of FIG. 8. The cellular accessbase station 821 can operate according to common wireless accessprotocols such as GSM, CDMA, TDMA, UMTS, WiMax, SDR, LTE, and so on.Other present and next generation wireless network technologies can beused by one or more embodiments of the subject disclosure. Accordingly,multiple wireline and wireless communication technologies can be used bythe CDs of FIG. 8.

Cellular phones supporting LTE can support packet-switched voice andpacket-switched data communications and thus may operate asIMS-compliant mobile devices. In this embodiment, the cellular basestation 821 may communicate directly with the IMS network 850 as shownby the arrow connecting the cellular base station 821 and the P-CSCF816.

Alternative forms of a CSCF can operate in a device, system, component,or other form of centralized or distributed hardware and/or software.Indeed, a respective CSCF may be embodied as a respective CSCF systemhaving one or more computers or servers, either centralized ordistributed, where each computer or server may be configured to performor provide, in whole or in part, any method, step, or functionalitydescribed herein in accordance with a respective CSCF. Likewise, otherfunctions, servers and computers described herein, including but notlimited to, the HSS, the ENUM server, the BGCF, and the MGCF, can beembodied in a respective system having one or more computers or servers,either centralized or distributed, where each computer or server may beconfigured to perform or provide, in whole or in part, any method, step,or functionality described herein in accordance with a respectivefunction, server, or computer.

The server 817 can perform function 874 (which can be embodied inhardware and/or software) which includes enable co-registration of twoor more access networks, such as enabling registration of an end userdevice with a WiFi network while maintaining the registration of the enduser device with respect to a RAN. Server 817 can perform function 874and thereby provide service continuity to the CDs 801, 802, 803 and 805of FIG. 8 over different access networks. CDs 801, 802, 803 and 805 canbe adapted with hardware and/or software to perform function 872 toutilize the co-registration and service continuity enabled by the server817. Software 872 can include dedicated user agents that run on the enduser devices which are dedicated to particular access networks tofacilitate co-registration via the IMS network 850 by the end userdevice to those access networks.

For illustration purposes only, the terms S-CSCF, P-CSCF, I-CSCF, and soon, can be server devices, but may be referred to in the subjectdisclosure without the word “server.” It is also understood that anyform of a CSCF server can operate in a device, system, component, orother form of centralized or distributed hardware and software. It isfurther noted that these terms and other terms such as DIAMETER commandsare terms can include features, methodologies, and/or fields that may bedescribed in whole or in part by standards bodies such as 3^(rd)Generation Partnership Project (3GPP). It is further noted that some orall embodiments of the subject disclosure may in whole or in partmodify, supplement, or otherwise supersede final or proposed standardspublished and promulgated by 3GPP.

A number of the exemplary embodiments describe a co-registration processfor two or more access networks which is facilitated by an IMS core,such as through use of a proxy SIP REGISTRAR server. The exemplaryembodiments can perform the co-registration process in a number ofdifferent ways utilizing various networks, systems or components thatmay or may not include the IMS core or the proxy SIP REGISTRAR server.In one embodiment, the co-registration process within an IMS core can bea dedicated process handled by another network element of the IMS corethat is in communication with the proxy SIP REGISTRAR server

Some of the exemplary embodiments describe co-registration of differentaccess networks (e.g., a RAN and a WiFi access network). One or more ofthe exemplary embodiments can enable co-registration of the same typesof access networks that are otherwise different networks, such asco-registration of first and second WiFi access networks that aremanaged by different service providers. In one embodiment, theco-registration of the same types of networks can enable flexibility inselection for the end user device such as based on costs of thedifferent providers, compatible services of the different providers, andso forth. In other embodiments the co-registration can be a combinationof different access network types and same access network types.

FIG. 9 depicts an illustrative embodiment of a communication device 900.Communication device 900 can serve in whole or in part as anillustrative embodiment of the devices depicted in FIGS. 1-6 and 8.Communication device 900 in whole or in part can represent any of thecommunication devices described in FIGS. 1-6 and 8 and can be configuredto perform all or portions of method 700 of FIG. 7.

Communication device 900 can comprise a wireline and/or wirelesstransceiver 902 (herein transceiver 902), a user interface (UI) 904, apower supply 914, a location receiver 916, a motion sensor 918, anorientation sensor 920, and a controller 906 for managing operationsthereof. The transceiver 902 can support short-range or long-rangewireless access technologies such as Bluetooth®, ZigBee®, WiFi, DECT, orcellular communication technologies, just to mention a few (Bluetooth®and ZigBee® are trademarks registered by the Bluetooth® Special InterestGroup and the ZigBee® Alliance, respectively). Cellular technologies caninclude, for example, CDMA-1X, UMTS/HSDPA, GSM/GPRS, TDMA/EDGE, EV/DO,WiMAX, SDR, LTE, as well as other next generation wireless communicationtechnologies as they arise. The transceiver 902 can also be adapted tosupport circuit-switched wireline access technologies (such as PSTN),packet-switched wireline access technologies (such as TCP/IP, VoIP,etc.), and combinations thereof.

The UI 904 can include a depressible or touch-sensitive keypad 908 witha navigation mechanism such as a roller ball, a joystick, a mouse, or anavigation disk for manipulating operations of the communication device900. The keypad 908 can be an integral part of a housing assembly of thecommunication device 900 or an independent device operably coupledthereto by a tethered wireline interface (such as a USB cable) or awireless interface supporting for example Bluetooth®. The keypad 908 canrepresent a numeric keypad commonly used by phones, and/or a QWERTYkeypad with alphanumeric keys. The UI 904 can further include a display910 such as monochrome or color LCD (Liquid Crystal Display), OLED(Organic Light Emitting Diode) or other suitable display technology forconveying images to an end user of the communication device 900. In anembodiment where the display 910 is touch-sensitive, a portion or all ofthe keypad 908 can be presented by way of the display 910 withnavigation features.

The display 910 can use touch screen technology to also serve as a userinterface for detecting user input. As a touch screen display, thecommunication device 900 can be adapted to present a user interface withgraphical user interface (GUI) elements that can be selected by a userwith a touch of a finger. The touch screen display 910 can be equippedwith capacitive, resistive or other forms of sensing technology todetect how much surface area of a user's finger has been placed on aportion of the touch screen display. This sensing information can beused to control the manipulation of the GUI elements or other functionsof the user interface. The display 910 can be an integral part of thehousing assembly of the communication device 900 or an independentdevice communicatively coupled thereto by a tethered wireline interface(such as a cable) or a wireless interface.

The UI 904 can also include an audio system 912 that utilizes audiotechnology for conveying low volume audio (such as audio heard inproximity of a human ear) and high volume audio (such as speakerphonefor hands free operation). The audio system 912 can further include amicrophone for receiving audible signals of an end user. The audiosystem 912 can also be used for voice recognition applications. The UI904 can further include an image sensor 913 such as a charged coupleddevice (CCD) camera for capturing still or moving images.

The power supply 914 can utilize common power management technologiessuch as replaceable and rechargeable batteries, supply regulationtechnologies, and/or charging system technologies for supplying energyto the components of the communication device 900 to facilitatelong-range or short-range portable applications. Alternatively, or incombination, the charging system can utilize external power sources suchas DC power supplied over a physical interface such as a USB port orother suitable tethering technologies.

The location receiver 916 can utilize location technology such as aglobal positioning system (GPS) receiver capable of assisted GPS foridentifying a location of the communication device 900 based on signalsgenerated by a constellation of GPS satellites, which can be used forfacilitating location services such as navigation. The motion sensor 918can utilize motion sensing technology such as an accelerometer, agyroscope, or other suitable motion sensing technology to detect motionof the communication device 900 in three-dimensional space. Theorientation sensor 920 can utilize orientation sensing technology suchas a magnetometer to detect the orientation of the communication device900 (north, south, west, and east, as well as combined orientations indegrees, minutes, or other suitable orientation metrics).

The communication device 900 can use the transceiver 902 to alsodetermine a proximity to a cellular, WiFi, Bluetooth®, or other wirelessaccess points by sensing techniques such as utilizing a received signalstrength indicator (RSSI) and/or signal time of arrival (TOA) or time offlight (TOF) measurements. The controller 906 can utilize computingtechnologies such as a microprocessor, a digital signal processor (DSP),programmable gate arrays, application specific integrated circuits,and/or a video processor with associated storage memory such as Flash,ROM, RAM, SRAM, DRAM or other storage technologies for executingcomputer instructions, controlling, and processing data supplied by theaforementioned components of the communication device 900.

Other components not shown in FIG. 9 can be used in one or moreembodiments of the subject disclosure. For instance, the communicationdevice 900 can include a reset button (not shown). The reset button canbe used to reset the controller 906 of the communication device 900. Inyet another embodiment, the communication device 900 can also include afactory default setting button positioned, for example, below a smallhole in a housing assembly of the communication device 900 to force thecommunication device 900 to re-establish factory settings. In thisembodiment, a user can use a protruding object such as a pen or paperclip tip to reach into the hole and depress the default setting button.The communication device 900 can also include a slot for adding orremoving an identity module such as a Subscriber Identity Module (SIM)card. SIM cards can be used for identifying subscriber services,executing programs, storing subscriber data, and so forth.

The communication device 900 as described herein can operate with moreor less of the circuit components shown in FIG. 9. These variantembodiments can be used in one or more embodiments of the subjectdisclosure.

The communication device 900 can be adapted to perform the functions ofdevices of FIGS. 1-6 and 8. It will be appreciated that thecommunication device 900 can also represent other devices that canoperate in systems associated with FIGS. 1-6 and 8. The controller 906can be adapted in various embodiments to perform the functions 872and/or 874 including performing co-registration, detecting triggeringevents for initiating the co-registration, performing service transferover a different access network utilizing co-registration, detectingtriggering events for initiating the service transfer over the differentaccess network utilizing the co-registration.

Upon reviewing the aforementioned embodiments, it would be evident to anartisan with ordinary skill in the art that said embodiments can bemodified, reduced, or enhanced without departing from the scope of theclaims described below. For example, co-registration can be performedwith more than two access networks. In one or more embodiments,performing co-registration and/or performing session transfer to the newaccess network according to co-registration can be based on a devicenegotiation process that takes into account various factors, such asuser preferences, end user device performance parameters, networkpreferences and/or network performance parameters.

One or more exemplary embodiments can provide information to the enduser indicating when a co-registration has been initiated or completed.For example, a WiFi icon can be displayed on the touch screen display910 so that a user knows that the device 900 has registered with a WiFiaccess network. In one embodiment, manipulation of the co-registrationicon can enable a user to permit or deny a transfer of a communicationsession to another access network, such as a drag and drop of theco-registration icon into a delete bin shown on the display 910. Inanother embodiment, co-registration icons can be displayed on thedisplay 910 to enable the end user to select among different availableaccess networks. For example, a group of available access networks (thatthe end user device has co-registered with) can be displayed in aprioritized list to facilitate a selection by the end user. In oneembodiment, the icons can include information with respect to the accessnetworks to facilitate the selection such as predicted signal strength,network traffic conditions, costs, available services, and so forth. Inone embodiment, the size of the icon can be adjusted to representdifferent features of the access networks such as providing larger iconsfor access networks that are predicted to have better quality of serviceor signal strength.

In another embodiment, icons can be presented to enable adjusting thecommunication session when it is switched to the new access network. Forexample, an icon can be presented that shows that the voice callcommunication session currently occurring over the RAN can be adjustedto a voice/video call when the session is seamlessly transferred over toa WiFi access networks based on the co-registration process.Combinations of these features can also be utilized such as showingavailable networks and showing available services (with or without otherinformation such as cost) for each of the available networks. Otherembodiments can be used in the subject disclosure.

It should be understood that devices described in the exemplaryembodiments can be in communication with each other via various wirelessand/or wired methodologies. The methodologies can be links that aredescribed as coupled, connected and so forth, which can includeunidirectional and/or bidirectional communication over wireless pathsand/or wired paths that utilize one or more of various protocols ormethodologies, where the coupling and/or connection can be direct (e.g.,no intervening processing device) and/or indirect (e.g., an intermediaryprocessing device such as a router).

FIG. 10 depicts an exemplary diagrammatic representation of a machine inthe form of a computer system 1000 within which a set of instructions,when executed, may cause the machine to perform any one or more of themethods described above. One or more instances of the machine canoperate, for example, as the end user device and/or the SIP REGISTRARserver to enable co-registration of an end user device with multipleaccess networks and/or to enable service continuity for the end userdevice between different access networks where co-registration hasoccurred. In some embodiments, the machine may be connected (e.g., usinga network 1026) to other machines. In a networked deployment, themachine may operate in the capacity of a server or a client user machinein a server-client user network environment, or as a peer machine in apeer-to-peer (or distributed) network environment.

The machine may comprise a server computer, a client user computer, apersonal computer (PC), a tablet, a smart phone, a laptop computer, adesktop computer, a control system, a network router, switch or bridge,or any machine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. It will beunderstood that a communication device of the subject disclosureincludes broadly any electronic device that provides voice, video,messaging and/or data communication. Further, while a single machine isillustrated, the term “machine” shall also be taken to include anycollection of machines that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of the methodsdiscussed herein.

The computer system 1000 may include a processor (or controller) 1002(e.g., a central processing unit (CPU)), a graphics processing unit(GPU, or both), a main memory 1004 and a static memory 1006, whichcommunicate with each other via a bus 1008. The computer system 1000 mayfurther include a display unit 1010 (e.g., a liquid crystal display(LCD), a flat panel, or a solid state display). The computer system 1000may include an input device 1012 (e.g., a keyboard), a cursor controldevice 1014 (e.g., a mouse), a disk drive unit 1016, a signal generationdevice 1018 (e.g., a speaker or remote control) and a network interfacedevice 1020. In distributed environments, the embodiments described inthe subject disclosure can be adapted to utilize multiple display units1010 controlled by two or more computer systems 1000. In thisconfiguration, presentations described by the subject disclosure may inpart be shown in a first of the display units 1010, while the remainingportion is presented in a second of the display units 1010.

The disk drive unit 1016 may include a tangible computer-readablestorage medium 1022 on which is stored one or more sets of instructions(e.g., software 1024) embodying any one or more of the methods orfunctions described herein, including those methods illustrated above.The instructions 1024 may also reside, completely or at least partially,within the main memory 1004, the static memory 1006, and/or within theprocessor 1002 during execution thereof by the computer system 1000. Themain memory 1004 and the processor 1002 also may constitute tangiblecomputer-readable storage media.

Dedicated hardware implementations including, but not limited to,application specific integrated circuits, programmable logic arrays andother hardware devices can likewise be constructed to implement themethods described herein. Application specific integrated circuits andprogrammable logic array can use downloadable instructions for executingstate machines and/or circuit configurations to implement embodiments ofthe subject disclosure. Applications that may include the apparatus andsystems of various embodiments broadly include a variety of electronicand computer systems. Some embodiments implement functions in two ormore specific interconnected hardware modules or devices with relatedcontrol and data signals communicated between and through the modules,or as portions of an application-specific integrated circuit. Thus, theexample system is applicable to software, firmware, and hardwareimplementations.

In accordance with various embodiments of the subject disclosure, theoperations or methods described herein are intended for operation assoftware programs or instructions running on or executed by a computerprocessor or other computing device, and which may include other formsof instructions manifested as a state machine implemented with logiccomponents in an application specific integrated circuit or fieldprogrammable gate array. Furthermore, software implementations (e.g.,software programs, instructions, etc.) including, but not limited to,distributed processing or component/object distributed processing,parallel processing, or virtual machine processing can also beconstructed to implement the methods described herein. It is furthernoted that a computing device such as a processor, a controller, a statemachine or other suitable device for executing instructions to performoperations or methods may perform such operations directly or indirectlyby way of one or more intermediate devices directed by the computingdevice.

While the tangible computer-readable storage medium 1022 is shown in anexample embodiment to be a single medium, the term “tangiblecomputer-readable storage medium” should be taken to include a singlemedium or multiple media (e.g., a centralized or distributed database,and/or associated caches and servers) that store the one or more sets ofinstructions. The term “tangible computer-readable storage medium” shallalso be taken to include any non-transitory medium that is capable ofstoring or encoding a set of instructions for execution by the machineand that cause the machine to perform any one or more of the methods ofthe subject disclosure. The term “non-transitory” as in a non-transitorycomputer-readable storage includes without limitation memories, drives,devices and anything tangible but not a signal per se.

The term “tangible computer-readable storage medium” shall accordinglybe taken to include, but not be limited to: solid-state memories such asa memory card or other package that houses one or more read-only(non-volatile) memories, random access memories, or other re-writable(volatile) memories, a magneto-optical or optical medium such as a diskor tape, or other tangible media which can be used to store information.Accordingly, the disclosure is considered to include any one or more ofa tangible computer-readable storage medium, as listed herein andincluding art-recognized equivalents and successor media, in which thesoftware implementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the disclosure is not limited to such standards andprotocols. Each of the standards for Internet and other packet switchednetwork transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) representexamples of the state of the art. Such standards are from time-to-timesuperseded by faster or more efficient equivalents having essentiallythe same functions. Wireless standards for device detection (e.g.,RFID), short-range communications (e.g., Bluetooth®, WiFi, Zigbee), andlong-range communications (e.g., WiMAX, GSM, CDMA, LTE) can be used bycomputer system 1000.

The illustrations of embodiments described herein are intended toprovide a general understanding of the structure of various embodiments,and they are not intended to serve as a complete description of all theelements and features of apparatus and systems that might make use ofthe structures described herein. Many other embodiments will be apparentto those of skill in the art upon reviewing the above description. Theexemplary embodiments can include combinations of features and/or stepsfrom multiple embodiments. Other embodiments may be utilized and derivedtherefrom, such that structural and logical substitutions and changesmay be made without departing from the scope of this disclosure. Figuresare also merely representational and may not be drawn to scale. Certainproportions thereof may be exaggerated, while others may be minimizedAccordingly, the specification and drawings are to be regarded in anillustrative rather than a restrictive sense.

Although specific embodiments have been illustrated and describedherein, it should be appreciated that any arrangement calculated toachieve the same purpose may be substituted for the specific embodimentsshown. This disclosure is intended to cover any and all adaptations orvariations of various embodiments. Combinations of the aboveembodiments, and other embodiments not specifically described herein,can be used in the subject disclosure. In one or more embodiments,features that are positively recited can also be excluded from theembodiment with or without replacement by another component or step. Thesteps or functions described with respect to the exemplary processes ormethods can be performed in any order. The steps or functions describedwith respect to the exemplary processes or methods can be performedalone or in combination with other steps or functions (from otherembodiments or from other steps that have not been described).

Less than all of the steps or functions described with respect to theexemplary processes or methods can also be performed in one or more ofthe exemplary embodiments. Further, the use of numerical terms todescribe a device, component, step or function, such as first, second,third, and so forth, is not intended to describe an order or functionunless expressly stated so. The use of the terms first, second, thirdand so forth, is generally to distinguish between devices, components,steps or functions unless expressly stated otherwise. Additionally, oneor more devices or components described with respect to the exemplaryembodiments can facilitate one or more functions, where the facilitating(e.g., facilitating access or facilitating establishing a connection)can include less than every step needed to perform the function or caninclude all of the steps needed to perform the function.

In one or more embodiments, a processor (which can include a controlleror circuit) has been described that performs various functions. Itshould be understood that the processor can be multiple processors,which can include distributed processors or parallel processors in asingle machine or multiple machines. The processor can be used insupporting a virtual processing environment. The virtual processingenvironment may support one or more virtual machines representingcomputers, servers, or other computing devices. In such virtualmachines, components such as microprocessors and storage devices may bevirtualized or logically represented. The processor can include a statemachine, application specific integrated circuit, and/or programmablegate array including a Field PGA. In one or more embodiments, when aprocessor executes instructions to perform “operations”, this caninclude the processor performing the operations directly and/orfacilitating, directing, or cooperating with another device or componentto perform the operations.

The Abstract of the Disclosure is provided with the understanding thatit will not be used to interpret or limit the scope or meaning of theclaims. In addition, in the foregoing Detailed Description, it can beseen that various features are grouped together in a single embodimentfor the purpose of streamlining the disclosure. This method ofdisclosure is not to be interpreted as reflecting an intention that theclaimed embodiments require more features than are expressly recited ineach claim. Rather, as the following claims reflect, inventive subjectmatter lies in less than all features of a single disclosed embodiment.Thus the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separately claimedsubject matter.

What is claimed is:
 1. A method comprising: receiving, by a processingsystem including a processor, a first registration message generated ata mobile device; registering, by the processing system and in responseto the first registration message, the mobile device with a first accessnetwork to generate a first registration; receiving, by the processingsystem, a second registration message generated at the mobile device;and registering, by the processing system and in response to the secondregistration message, the mobile device with a second access network togenerate a second registration while the first registration ismaintained, wherein the first registration message and the secondregistration message are generated at least in part by a plurality ofuser agents communicating with a same registrar server, wherein therespective user agents communicate with the registrar server using asame public identifier and different private identifiers, and whereinthe first registration and the second registration use a sameauthentication and key agreement and are associated with a same serviceidentity module or a same subscriber key credential.
 2. The method ofclaim 1, wherein the plurality of user agents are resident on the mobiledevice.
 3. The method of claim 1, wherein the first access network is aradio access network, and wherein the second access network is awireless local area network.
 4. The method of claim 1, wherein thesecond registration is generated responsive to detection of a firsttriggering event by the mobile device, the processing system, or acombination thereof.
 5. The method of claim 4, wherein the firsttriggering event comprises a change in location of the mobile devicewith respect to a coverage area of the second access network.
 6. Themethod of claim 4, wherein the mobile device is engaged in acommunication session using the first access network, and wherein thecommunication session is transferred from the first access network tothe second access network responsive to detection of a second triggeringevent by the mobile device, the processing system, or a combinationthereof.
 7. The method of claim 6, further comprising monitoring, by theprocessing system, a network performance parameter of the first accessnetwork, a device performance parameter of the mobile device, or acombination thereof.
 8. The method of claim 7, wherein the networkperformance parameter represents a quality of service (QoS) for thecommunication session associated with the first access network, whereinthe second triggering event comprises the QoS falling below a threshold.9. The method of claim 1, further comprising receiving, by theprocessing system, an invitation message initiated by a first dedicateduser agent resident on the mobile device, and wherein the invitationmessage causes a transfer of a communication session from the firstaccess network to the second access network.
 10. The method of claim 1,further comprising receiving, by the processing system, a refer-tomessage initiated by a second dedicated user agent resident on themobile device, and wherein the refer-to message causes a transfer of acommunication session from the first access network to the second accessnetwork.
 11. A device comprising: a processing system including aprocessor; and a memory that stores executable instructions that, whenexecuted by the processing system, facilitate performance of operations,comprising: receiving a first registration message generated at a mobiledevice; registering, in response to the first registration message, themobile device with a first access network to generate a firstregistration, wherein the first access network comprises a radio accessnetwork; receiving, a second registration message generated at themobile device; and registering, in response to the second registrationmessage, the mobile device with a second access network to generate asecond registration while the first registration is maintained, whereinthe second access network comprises a wireless local area network,wherein the first registration message and the second registrationmessage are generated at least in part by a plurality of user agentscommunicating with a same registrar server, wherein the plurality ofuser agents are resident on the mobile device, wherein the respectiveuser agents communicate with the registrar server using a same publicidentifier and different private identifiers, and wherein the firstregistration and the second registration use a same authentication andkey agreement and are associated with a same service identity module ora same subscriber key credential.
 12. The device of claim 11, whereinthe second registration is generated responsive to detection of a firsttriggering event by the mobile device, the processing system, or acombination thereof.
 13. The device of claim 12, wherein a communicationsession is transferred from the first access network to the secondaccess network responsive to detection of a second triggering event bythe mobile device, the processing system, or a combination thereof. 14.The device of claim 11, wherein the operations further comprisereceiving an invitation message initiated by a first dedicated useragent resident on the mobile device, and wherein the invitation messagecauses a transfer of a communication session from the first accessnetwork to the second access network.
 15. The device of claim 11,wherein the operations further comprise receiving a refer-to messageinitiated by a second dedicated user agent resident on the mobiledevice, and wherein the refer-to message causes a transfer of acommunication session from the first access network to the second accessnetwork.
 16. A machine-readable storage medium, comprising executableinstructions that, when executed by a processing system including aprocessor, facilitate performance of operations comprising: receiving afirst registration message generated at a mobile device; registering, inresponse to the first registration message, the mobile device with afirst access network to generate a first registration; receiving, asecond registration message generated at the mobile device; andregistering, in response to the second registration message, the mobiledevice with a second access network to generate a second registrationwhile the first registration is maintained, wherein the firstregistration message and the second registration message are generatedat least in part by a plurality of user agents communicating with a sameregistrar server, wherein the user agents are resident on the mobiledevice, wherein the respective user agents communicate with theregistrar server using a same public identifier and different privateidentifiers, and wherein the first registration and the secondregistration use a same authentication and key agreement and areassociated with a same service identity module or a same subscriber keycredential, wherein the second registration is generated responsive todetection of a first triggering event by the mobile device, theprocessing system, or a combination thereof.
 17. The machine-readablestorage medium of claim 16, wherein the first triggering event comprisesa change in location of the mobile device with respect to a coveragearea of the second access network.
 18. The machine-readable storagemedium of claim 16, wherein a communication session is transferred fromthe first access network to the second access network responsive todetection of a second triggering event by the mobile device, theprocessing system, or a combination thereof.
 19. The machine-readablestorage medium of claim 16, wherein the operations further comprisereceiving an invitation message initiated by a first dedicated useragent resident on the mobile device, and wherein the invitation messagecauses a transfer of a communication session from the first accessnetwork to the second access network.
 20. The machine-readable storagemedium of claim 16, wherein the operations further comprise receiving arefer-to message initiated by a second dedicated user agent resident onthe mobile device, and wherein the refer-to message causes a transfer ofa communication session from the first access network to the secondaccess network.